Various pedestrian detection systems have been proposed before, mainly incorporating sensors mounted on the front of the vehicle, such as in the bumper or fender of the vehicle. Such detection systems can easily give a false output signal, causing inappropriate deployment of a safety device, for example, when striking an item such as road-cone or an animal.
The present invention seeks to provide an improved pedestrian detection system.
According to the present invention there is provided a pedestrian detection system provided on a motor vehicle, the motor vehicle having a hood or bonnet, the detection system including: a first sensor arrangement located more than about 0.5 meters behind the front end of the vehicle to detect the speed of and/or distance to a part of an object located in front of the vehicle, the part of the object extending above a predetermined height, the predetermined height being at least the height of the front edge of the hood or bonnet; and a second sensor arrangement comprising a sensor mounted in the front bumper or fender of the vehicle responsive to an impact of the vehicle with an object.
Preferably, the first sensor arrangement is a microwave radar.
Advantageously, the first sensor arrangement is an infra-red radar.
Conveniently, the first sensor arrangement is a camera.
Preferably, the camera operates in the visible spectrum.
Advantageously, the camera operates in the infra-red spectrum.
Conveniently, the first sensor arrangement is a stereo-camera arrangement.
Preferably, the first sensor arrangement is mounted on the exterior of the vehicle in front of a windscreen or windshield provided on the vehicle.
Advantageously, the first sensor arrangement is mounted on the vehicle behind the windscreen or windshield of the vehicle.
Conveniently, the first sensor arrangement is mounted above the windscreen.
Preferably, a pedestrian protection arrangement is provided, the detection system being configured to activate the pedestrian arrangement device in response to the first sensor arrangement detecting the distance below a threshold and/or a speed above a threshold.
Conveniently, threshold distance is less than the distance between the sensor and the front of the vehicle.
Preferably, the second sensor arrangement further includes an accelerometer.
Advantageously, the accelerometer is configured to provide a signal indicative of a crash situation and wherein, upon receipt of said signal, an internal safety device on the vehicle is actuated.
Preferably, the sensor mounted in the front bumper is a contact sensor.
Advantageously, the second sensor arrangement is a sensor that can discriminate objects lighter than a pedestrian.
Conveniently, the pedestrian protection arrangement is activated only if the first sensor arrangement detects a distance below a threshold and/or a speed above a threshold, and also the second sensor arrangement detects an object.
Preferably, the pedestrian protection arrangement has at least two modes of activation.
Advantageously, the pedestrian protection arrangement incorporates at least two pedestrian devices.
Conveniently, the pedestrian protection arrangement incorporates a lifter to lift the front part of the hood or bonnet, and a lifter to lift the rear part of the hood or bonnet, one mode of activation being the lifting of the front part of the hood or bonnet, a second mode of operation including additionally the lifting of the rear part of the hood or bonnet.
Preferably, the pedestrian protection arrangement includes a mechanism to lift the rear part of the hood or bonnet, and at least one air-bag to cover part of the windscreen and/or part of A-Pillars provided on the vehicle, one mode of activation comprising the lifting of only the rear part of the hood or bonnet, the second mode including additionally the activation of at least one air-bag.
Advantageously, different modes are activated in response to a signal dependent on the first sensor arrangement reaching different thresholds.
Conveniently, at least one of said different thresholds is dependent upon the vehicle speed as measured by a third sensor arrangement.